Datasheet

SS/TR
INH/UVLO
VOUT
STSEL
SS/TR
INH/UVLO
VOUT
STSEL
V
OUT1
R1
R2
V
OUT2
( )
( )
´
= W
OUT2
V 12.6
R1 k
0.803
( )
( )
´
= W
-
OUT2
0.803 R1
R2 k
V 0.803
SS/TR
INH/UVLO PWRGD
STSEL
SS/TR
INH/UVLO PWRGD
STSEL
UDG-11120
LMZ30602
www.ti.com SNVS997 –JULY 2013
Sequencing (SS/TR)
Many of the common power supply sequencing methods can be implemented using the SS/TR, INH and
PWRGD pins. The sequential method is illustrated in Figure 29 using two LMZ30602 devices. The PWRGD pin
of the first device is coupled to the INH pin of the second device which enables the second power supply once
the primary supply reaches regulation. Do not place a pull-up resistor on PWRGD in this configuration. Figure 30
shows sequential turn-on waveforms of two LMZ30602 devices.
Figure 29. Sequencing Schematic Figure 30. Sequencing Waveforms
Simultaneous power supply sequencing can be implemented by connecting the resistor network of R1 and R2
shown in Figure 31 to the output of the power supply that needs to be tracked or to another voltage reference
source. Figure 32 shows simultaneous turn-on waveforms of two LMZ30602 devices. Use Equation 3 and
Equation 4 to calculate the values of R1 and R2.
(3) (4)
Figure 31. Simultaneous Tracking Schematic Figure 32. Simultaneous Tracking Waveforms
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